Last month, Sunak reduced ambitions on a raft of green policies, including pushing back the ban on the sales of new petrol and diesel cars from 2030 to 2035; phasing out 80 per cent of new gas boilers, rather than all of them, by 2035; delaying the ban on off-grid oil boilers to 2035; pledging to not introduce new home energy efficiency regulations for landlords or homeowners; and ruling out taxes to discourage flying.

The CCC said that electric vehicles (EVs) will be “significantly” cheaper than petrol and diesel vehicles to own and operate over their lifetimes, so the undermining of their roll-out will ultimately increase costs for consumers.

However, it did find that the decision would only have a small direct impact on future emissions, due to a new mandate ensuring that 80 per cent of new cars sold by 2030 will be zero-emission.

Nevertheless, it was critical of the uncertainty that has been introduced by changing near-term targets and expressed concern...